1. Field of the Invention
The present invention relates to an electrical machine of horizontal design with a housing and with a bearing support arrangement, with integrated bearings, which is releasably connected to the end faces of the housing, the bearing support arrangement being made double-walled and box-like with reinforcing ribs located between the two walls, and supports being provided for receiving the bearings.
2. Description of the Prior Art
A bearing support of this type has already been proposed, for example, in Swiss Patent Application No. 10,331/79-7, or German Patent Application No. P 2,950 570. This is intended for large turbo-generators and is therefore correspondingly expensive.
In a bearing support known in the art, the stator of an electrical machine is located on a frame-like supporting cradle, this cradle being fastened on a base-frame. The supports for the rotor are located in cross-struts of the cradle and can be adjusted and fixed by means of special adjusting elements. The entire frame-like construction of the cradle is covered with removable casing panels, these panels forming, at the same time, housing parts and cooling-air guides (U.S. Pat. No. 3,064,152).
Since, in this design of a bearing support, the cradle, receiving the stator, and the housing parts holding the bearings are mounted on a common base-frame, all the out-of-balance forces caused by the rotor are transmitted into the foundation via the stator housing parts. A further disadvantage of a bearing arrangement of this type is the relatively great anisotropy of the rotor mounting, that is to say different elasticities of the bearing support in the horizontal and the vertical direction, this leading to a lower critical speed for flexural distortion and to an increased speed range in which resonant vibrations can occur.